[rust-lightning] / lightning / src / ln / onion_utils.rs

// This file is Copyright its original authors, visible in version control
// history.
//
// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
// or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
// You may not use this file except in accordance with one or both of these
// licenses.

use ln::{PaymentHash, PaymentPreimage, PaymentSecret};
use ln::channelmanager::HTLCSource;
use ln::msgs;
use ln::wire::Encode;
use routing::gossip::NetworkUpdate;
use routing::router::RouteHop;
use util::chacha20::{ChaCha20, ChaChaReader};
use util::errors::{self, APIError};
use util::ser::{Readable, ReadableArgs, Writeable, LengthCalculatingWriter};
use util::logger::Logger;

use bitcoin::hashes::{Hash, HashEngine};
use bitcoin::hashes::cmp::fixed_time_eq;
use bitcoin::hashes::hmac::{Hmac, HmacEngine};
use bitcoin::hashes::sha256::Hash as Sha256;

use bitcoin::secp256k1::{SecretKey, PublicKey, Scalar};
use bitcoin::secp256k1::Secp256k1;
use bitcoin::secp256k1::ecdh::SharedSecret;
use bitcoin::secp256k1;

use prelude::*;
use io::{Cursor, Read};
use core::convert::{AsMut, TryInto};
use core::ops::Deref;

pub(crate) struct OnionKeys {
        #[cfg(test)]
        pub(crate) shared_secret: SharedSecret,
        #[cfg(test)]
        pub(crate) blinding_factor: [u8; 32],
        pub(crate) ephemeral_pubkey: PublicKey,
        pub(crate) rho: [u8; 32],
        pub(crate) mu: [u8; 32],
}

#[inline]
pub(crate) fn gen_rho_from_shared_secret(shared_secret: &[u8]) -> [u8; 32] {
        assert_eq!(shared_secret.len(), 32);
        let mut hmac = HmacEngine::<Sha256>::new(&[0x72, 0x68, 0x6f]); // rho
        hmac.input(&shared_secret);
        Hmac::from_engine(hmac).into_inner()
}

#[inline]
pub(crate) fn gen_rho_mu_from_shared_secret(shared_secret: &[u8]) -> ([u8; 32], [u8; 32]) {
        assert_eq!(shared_secret.len(), 32);
        ({
                let mut hmac = HmacEngine::<Sha256>::new(&[0x72, 0x68, 0x6f]); // rho
                hmac.input(&shared_secret);
                Hmac::from_engine(hmac).into_inner()
        },
        {
                let mut hmac = HmacEngine::<Sha256>::new(&[0x6d, 0x75]); // mu
                hmac.input(&shared_secret);
                Hmac::from_engine(hmac).into_inner()
        })
}

#[inline]
pub(super) fn gen_um_from_shared_secret(shared_secret: &[u8]) -> [u8; 32] {
        assert_eq!(shared_secret.len(), 32);
        let mut hmac = HmacEngine::<Sha256>::new(&[0x75, 0x6d]); // um
        hmac.input(&shared_secret);
        Hmac::from_engine(hmac).into_inner()
}

#[inline]
pub(super) fn gen_ammag_from_shared_secret(shared_secret: &[u8]) -> [u8; 32] {
        assert_eq!(shared_secret.len(), 32);
        let mut hmac = HmacEngine::<Sha256>::new(&[0x61, 0x6d, 0x6d, 0x61, 0x67]); // ammag
        hmac.input(&shared_secret);
        Hmac::from_engine(hmac).into_inner()
}

pub(crate) fn next_hop_packet_pubkey<T: secp256k1::Signing + secp256k1::Verification>(secp_ctx: &Secp256k1<T>, packet_pubkey: PublicKey, packet_shared_secret: &[u8; 32]) -> Result<PublicKey, secp256k1::Error> {
        let blinding_factor = {
                let mut sha = Sha256::engine();
                sha.input(&packet_pubkey.serialize()[..]);
                sha.input(packet_shared_secret);
                Sha256::from_engine(sha).into_inner()
        };

        packet_pubkey.mul_tweak(secp_ctx, &Scalar::from_be_bytes(blinding_factor).unwrap())
}

// can only fail if an intermediary hop has an invalid public key or session_priv is invalid
#[inline]
pub(super) fn construct_onion_keys_callback<T: secp256k1::Signing, FType: FnMut(SharedSecret, [u8; 32], PublicKey, &RouteHop, usize)> (secp_ctx: &Secp256k1<T>, path: &Vec<RouteHop>, session_priv: &SecretKey, mut callback: FType) -> Result<(), secp256k1::Error> {
        let mut blinded_priv = session_priv.clone();
        let mut blinded_pub = PublicKey::from_secret_key(secp_ctx, &blinded_priv);

        for (idx, hop) in path.iter().enumerate() {
                let shared_secret = SharedSecret::new(&hop.pubkey, &blinded_priv);

                let mut sha = Sha256::engine();
                sha.input(&blinded_pub.serialize()[..]);
                sha.input(shared_secret.as_ref());
                let blinding_factor = Sha256::from_engine(sha).into_inner();

                let ephemeral_pubkey = blinded_pub;

                blinded_priv = blinded_priv.mul_tweak(&Scalar::from_be_bytes(blinding_factor).unwrap())?;
                blinded_pub = PublicKey::from_secret_key(secp_ctx, &blinded_priv);

                callback(shared_secret, blinding_factor, ephemeral_pubkey, hop, idx);
        }

        Ok(())
}

// can only fail if an intermediary hop has an invalid public key or session_priv is invalid
pub(super) fn construct_onion_keys<T: secp256k1::Signing>(secp_ctx: &Secp256k1<T>, path: &Vec<RouteHop>, session_priv: &SecretKey) -> Result<Vec<OnionKeys>, secp256k1::Error> {
        let mut res = Vec::with_capacity(path.len());

        construct_onion_keys_callback(secp_ctx, path, session_priv, |shared_secret, _blinding_factor, ephemeral_pubkey, _, _| {
                let (rho, mu) = gen_rho_mu_from_shared_secret(shared_secret.as_ref());

                res.push(OnionKeys {
                        #[cfg(test)]
                        shared_secret,
                        #[cfg(test)]
                        blinding_factor: _blinding_factor,
                        ephemeral_pubkey,
                        rho,
                        mu,
                });
        })?;

        Ok(res)
}

/// returns the hop data, as well as the first-hop value_msat and CLTV value we should send.
pub(super) fn build_onion_payloads(path: &Vec<RouteHop>, total_msat: u64, payment_secret_option: &Option<PaymentSecret>, starting_htlc_offset: u32, keysend_preimage: &Option<PaymentPreimage>) -> Result<(Vec<msgs::OnionHopData>, u64, u32), APIError> {
        let mut cur_value_msat = 0u64;
        let mut cur_cltv = starting_htlc_offset;
        let mut last_short_channel_id = 0;
        let mut res: Vec<msgs::OnionHopData> = Vec::with_capacity(path.len());

        for (idx, hop) in path.iter().rev().enumerate() {
                // First hop gets special values so that it can check, on receipt, that everything is
                // exactly as it should be (and the next hop isn't trying to probe to find out if we're
                // the intended recipient).
                let value_msat = if cur_value_msat == 0 { hop.fee_msat } else { cur_value_msat };
                let cltv = if cur_cltv == starting_htlc_offset { hop.cltv_expiry_delta + starting_htlc_offset } else { cur_cltv };
                res.insert(0, msgs::OnionHopData {
                        format: if hop.node_features.supports_variable_length_onion() {
                                if idx == 0 {
                                        msgs::OnionHopDataFormat::FinalNode {
                                                payment_data: if let &Some(ref payment_secret) = payment_secret_option {
                                                        Some(msgs::FinalOnionHopData {
                                                                payment_secret: payment_secret.clone(),
                                                                total_msat,
                                                        })
                                                } else { None },
                                                keysend_preimage: *keysend_preimage,
                                        }
                                } else {
                                        msgs::OnionHopDataFormat::NonFinalNode {
                                                short_channel_id: last_short_channel_id,
                                        }
                                }
                        } else {
                                msgs::OnionHopDataFormat::Legacy {
                                        short_channel_id: last_short_channel_id,
                                }
                        },
                        amt_to_forward: value_msat,
                        outgoing_cltv_value: cltv,
                });
                cur_value_msat += hop.fee_msat;
                if cur_value_msat >= 21000000 * 100000000 * 1000 {
                        return Err(APIError::RouteError{err: "Channel fees overflowed?"});
                }
                cur_cltv += hop.cltv_expiry_delta as u32;
                if cur_cltv >= 500000000 {
                        return Err(APIError::RouteError{err: "Channel CLTV overflowed?"});
                }
                last_short_channel_id = hop.short_channel_id;
        }
        Ok((res, cur_value_msat, cur_cltv))
}

/// Length of the onion data packet. Before TLV-based onions this was 20 65-byte hops, though now
/// the hops can be of variable length.
pub(crate) const ONION_DATA_LEN: usize = 20*65;

#[inline]
fn shift_slice_right(arr: &mut [u8], amt: usize) {
        for i in (amt..arr.len()).rev() {
                arr[i] = arr[i-amt];
        }
        for i in 0..amt {
                arr[i] = 0;
        }
}

pub(super) fn route_size_insane(payloads: &Vec<msgs::OnionHopData>) -> bool {
        let mut len = 0;
        for payload in payloads.iter() {
                let mut payload_len = LengthCalculatingWriter(0);
                payload.write(&mut payload_len).expect("Failed to calculate length");
                assert!(payload_len.0 + 32 < ONION_DATA_LEN);
                len += payload_len.0 + 32;
                if len > ONION_DATA_LEN {
                        return true;
                }
        }
        false
}

/// panics if route_size_insane(payloads)
pub(super) fn construct_onion_packet(payloads: Vec<msgs::OnionHopData>, onion_keys: Vec<OnionKeys>, prng_seed: [u8; 32], associated_data: &PaymentHash) -> msgs::OnionPacket {
        let mut packet_data = [0; ONION_DATA_LEN];

        let mut chacha = ChaCha20::new(&prng_seed, &[0; 8]);
        chacha.process(&[0; ONION_DATA_LEN], &mut packet_data);

        construct_onion_packet_with_init_noise::<_, _>(
                payloads, onion_keys, FixedSizeOnionPacket(packet_data), Some(associated_data))
}

#[cfg(test)]
// Used in testing to write bogus OnionHopDatas, which is otherwise not representable in
// msgs::OnionHopData.
pub(super) fn construct_onion_packet_bogus_hopdata<HD: Writeable>(payloads: Vec<HD>, onion_keys: Vec<OnionKeys>, prng_seed: [u8; 32], associated_data: &PaymentHash) -> msgs::OnionPacket {
        let mut packet_data = [0; ONION_DATA_LEN];

        let mut chacha = ChaCha20::new(&prng_seed, &[0; 8]);
        chacha.process(&[0; ONION_DATA_LEN], &mut packet_data);

        construct_onion_packet_with_init_noise::<_, _>(
                payloads, onion_keys, FixedSizeOnionPacket(packet_data), Some(associated_data))
}

/// Since onion message packets and onion payment packets have different lengths but are otherwise
/// identical, we use this trait to allow `construct_onion_packet_with_init_noise` to return either
/// type.
pub(crate) trait Packet {
        type Data: AsMut<[u8]>;
        fn new(pubkey: PublicKey, hop_data: Self::Data, hmac: [u8; 32]) -> Self;
}

// Needed for rustc versions older than 1.47 to avoid E0277: "arrays only have std trait
// implementations for lengths 0..=32".
pub(crate) struct FixedSizeOnionPacket(pub(crate) [u8; ONION_DATA_LEN]);

impl AsMut<[u8]> for FixedSizeOnionPacket {
        fn as_mut(&mut self) -> &mut [u8] {
                &mut self.0
        }
}

pub(crate) fn payloads_serialized_length<HD: Writeable>(payloads: &Vec<HD>) -> usize {
        payloads.iter().map(|p| p.serialized_length() + 32 /* HMAC */).sum()
}

/// panics if payloads_serialized_length(payloads) > packet_data_len
pub(crate) fn construct_onion_message_packet<HD: Writeable, P: Packet<Data = Vec<u8>>>(
        payloads: Vec<HD>, onion_keys: Vec<OnionKeys>, prng_seed: [u8; 32], packet_data_len: usize) -> P
{
        let mut packet_data = vec![0; packet_data_len];

        let mut chacha = ChaCha20::new(&prng_seed, &[0; 8]);
        chacha.process_in_place(&mut packet_data);

        construct_onion_packet_with_init_noise::<_, _>(payloads, onion_keys, packet_data, None)
}

/// panics if payloads_serialized_length(payloads) > packet_data.len()
fn construct_onion_packet_with_init_noise<HD: Writeable, P: Packet>(
        mut payloads: Vec<HD>, onion_keys: Vec<OnionKeys>, mut packet_data: P::Data, associated_data: Option<&PaymentHash>) -> P
{
        let filler = {
                let packet_data = packet_data.as_mut();
                const ONION_HOP_DATA_LEN: usize = 65; // We may decrease this eventually after TLV is common
                let mut res = Vec::with_capacity(ONION_HOP_DATA_LEN * (payloads.len() - 1));

                let mut pos = 0;
                for (i, (payload, keys)) in payloads.iter().zip(onion_keys.iter()).enumerate() {
                        if i == payloads.len() - 1 { break; }

                        let mut chacha = ChaCha20::new(&keys.rho, &[0u8; 8]);
                        for _ in 0..(packet_data.len() - pos) { // TODO: Batch this.
                                let mut dummy = [0; 1];
                                chacha.process_in_place(&mut dummy); // We don't have a seek function :(
                        }

                        let mut payload_len = LengthCalculatingWriter(0);
                        payload.write(&mut payload_len).expect("Failed to calculate length");
                        pos += payload_len.0 + 32;
                        assert!(pos <= packet_data.len());

                        res.resize(pos, 0u8);
                        chacha.process_in_place(&mut res);
                }
                res
        };

        let mut hmac_res = [0; 32];
        for (i, (payload, keys)) in payloads.iter_mut().zip(onion_keys.iter()).rev().enumerate() {
                let mut payload_len = LengthCalculatingWriter(0);
                payload.write(&mut payload_len).expect("Failed to calculate length");

                let packet_data = packet_data.as_mut();
                shift_slice_right(packet_data, payload_len.0 + 32);
                packet_data[0..payload_len.0].copy_from_slice(&payload.encode()[..]);
                packet_data[payload_len.0..(payload_len.0 + 32)].copy_from_slice(&hmac_res);

                let mut chacha = ChaCha20::new(&keys.rho, &[0u8; 8]);
                chacha.process_in_place(packet_data);

                if i == 0 {
                        packet_data[ONION_DATA_LEN - filler.len()..ONION_DATA_LEN].copy_from_slice(&filler[..]);
                }

                let mut hmac = HmacEngine::<Sha256>::new(&keys.mu);
                hmac.input(packet_data);
                if let Some(associated_data) = associated_data {
                        hmac.input(&associated_data.0[..]);
                }
                hmac_res = Hmac::from_engine(hmac).into_inner();
        }

        P::new(onion_keys.first().unwrap().ephemeral_pubkey, packet_data, hmac_res)
}

/// Encrypts a failure packet. raw_packet can either be a
/// msgs::DecodedOnionErrorPacket.encode() result or a msgs::OnionErrorPacket.data element.
pub(super) fn encrypt_failure_packet(shared_secret: &[u8], raw_packet: &[u8]) -> msgs::OnionErrorPacket {
        let ammag = gen_ammag_from_shared_secret(&shared_secret);

        let mut packet_crypted = Vec::with_capacity(raw_packet.len());
        packet_crypted.resize(raw_packet.len(), 0);
        let mut chacha = ChaCha20::new(&ammag, &[0u8; 8]);
        chacha.process(&raw_packet, &mut packet_crypted[..]);
        msgs::OnionErrorPacket {
                data: packet_crypted,
        }
}

pub(super) fn build_failure_packet(shared_secret: &[u8], failure_type: u16, failure_data: &[u8]) -> msgs::DecodedOnionErrorPacket {
        assert_eq!(shared_secret.len(), 32);
        assert!(failure_data.len() <= 256 - 2);

        let um = gen_um_from_shared_secret(&shared_secret);

        let failuremsg = {
                let mut res = Vec::with_capacity(2 + failure_data.len());
                res.push(((failure_type >> 8) & 0xff) as u8);
                res.push(((failure_type >> 0) & 0xff) as u8);
                res.extend_from_slice(&failure_data[..]);
                res
        };
        let pad = {
                let mut res = Vec::with_capacity(256 - 2 - failure_data.len());
                res.resize(256 - 2 - failure_data.len(), 0);
                res
        };
        let mut packet = msgs::DecodedOnionErrorPacket {
                hmac: [0; 32],
                failuremsg,
                pad,
        };

        let mut hmac = HmacEngine::<Sha256>::new(&um);
        hmac.input(&packet.encode()[32..]);
        packet.hmac = Hmac::from_engine(hmac).into_inner();

        packet
}

#[inline]
pub(super) fn build_first_hop_failure_packet(shared_secret: &[u8], failure_type: u16, failure_data: &[u8]) -> msgs::OnionErrorPacket {
        let failure_packet = build_failure_packet(shared_secret, failure_type, failure_data);
        encrypt_failure_packet(shared_secret, &failure_packet.encode()[..])
}

/// Process failure we got back from upstream on a payment we sent (implying htlc_source is an
/// OutboundRoute).
/// Returns update, a boolean indicating that the payment itself failed, the short channel id of
/// the responsible channel, and the error code.
#[inline]
pub(super) fn process_onion_failure<T: secp256k1::Signing, L: Deref>(secp_ctx: &Secp256k1<T>, logger: &L, htlc_source: &HTLCSource, mut packet_decrypted: Vec<u8>) -> (Option<NetworkUpdate>, Option<u64>, bool, Option<u16>, Option<Vec<u8>>) where L::Target: Logger {
        if let &HTLCSource::OutboundRoute { ref path, ref session_priv, ref first_hop_htlc_msat, .. } = htlc_source {
                let mut res = None;
                let mut htlc_msat = *first_hop_htlc_msat;
                let mut error_code_ret = None;
                let mut error_packet_ret = None;
                let mut is_from_final_node = false;

                // Handle packed channel/node updates for passing back for the route handler
                construct_onion_keys_callback(secp_ctx, path, session_priv, |shared_secret, _, _, route_hop, route_hop_idx| {
                        if res.is_some() { return; }

                        let amt_to_forward = htlc_msat - route_hop.fee_msat;
                        htlc_msat = amt_to_forward;

                        let ammag = gen_ammag_from_shared_secret(shared_secret.as_ref());

                        let mut decryption_tmp = Vec::with_capacity(packet_decrypted.len());
                        decryption_tmp.resize(packet_decrypted.len(), 0);
                        let mut chacha = ChaCha20::new(&ammag, &[0u8; 8]);
                        chacha.process(&packet_decrypted, &mut decryption_tmp[..]);
                        packet_decrypted = decryption_tmp;

                        // The failing hop includes either the inbound channel to the recipient or the outbound
                        // channel from the current hop (i.e., the next hop's inbound channel).
                        is_from_final_node = route_hop_idx + 1 == path.len();
                        let failing_route_hop = if is_from_final_node { route_hop } else { &path[route_hop_idx + 1] };

                        if let Ok(err_packet) = msgs::DecodedOnionErrorPacket::read(&mut Cursor::new(&packet_decrypted)) {
                                let um = gen_um_from_shared_secret(shared_secret.as_ref());
                                let mut hmac = HmacEngine::<Sha256>::new(&um);
                                hmac.input(&err_packet.encode()[32..]);

                                if fixed_time_eq(&Hmac::from_engine(hmac).into_inner(), &err_packet.hmac) {
                                        if let Some(error_code_slice) = err_packet.failuremsg.get(0..2) {
                                                const BADONION: u16 = 0x8000;
                                                const PERM: u16 = 0x4000;
                                                const NODE: u16 = 0x2000;
                                                const UPDATE: u16 = 0x1000;

                                                let error_code = u16::from_be_bytes(error_code_slice.try_into().expect("len is 2"));
                                                error_code_ret = Some(error_code);
                                                error_packet_ret = Some(err_packet.failuremsg[2..].to_vec());

                                                let (debug_field, debug_field_size) = errors::get_onion_debug_field(error_code);

                                                // indicate that payment parameter has failed and no need to
                                                // update Route object
                                                let payment_failed = match error_code & 0xff {
                                                        15|16|17|18|19|23 => true,
                                                        _ => false,
                                                } && is_from_final_node; // PERM bit observed below even if this error is from the intermediate nodes

                                                let mut network_update = None;
                                                let mut short_channel_id = None;

                                                if error_code & BADONION == BADONION {
                                                        // If the error code has the BADONION bit set, always blame the channel
                                                        // from the node "originating" the error to its next hop. The
                                                        // "originator" is ultimately actually claiming that its counterparty
                                                        // is the one who is failing the HTLC.
                                                        // If the "originator" here isn't lying we should really mark the
                                                        // next-hop node as failed entirely, but we can't be confident in that,
                                                        // as it would allow any node to get us to completely ban one of its
                                                        // counterparties. Instead, we simply remove the channel in question.
                                                        network_update = Some(NetworkUpdate::ChannelFailure {
                                                                short_channel_id: failing_route_hop.short_channel_id,
                                                                is_permanent: true,
                                                        });
                                                } else if error_code & NODE == NODE {
                                                        let is_permanent = error_code & PERM == PERM;
                                                        network_update = Some(NetworkUpdate::NodeFailure { node_id: route_hop.pubkey, is_permanent });
                                                        short_channel_id = Some(route_hop.short_channel_id);
                                                } else if error_code & PERM == PERM {
                                                        if !payment_failed {
                                                                network_update = Some(NetworkUpdate::ChannelFailure {
                                                                        short_channel_id: failing_route_hop.short_channel_id,
                                                                        is_permanent: true,
                                                                });
                                                                short_channel_id = Some(failing_route_hop.short_channel_id);
                                                        }
                                                } else if error_code & UPDATE == UPDATE {
                                                        if let Some(update_len_slice) = err_packet.failuremsg.get(debug_field_size+2..debug_field_size+4) {
                                                                let update_len = u16::from_be_bytes(update_len_slice.try_into().expect("len is 2")) as usize;
                                                                if let Some(mut update_slice) = err_packet.failuremsg.get(debug_field_size + 4..debug_field_size + 4 + update_len) {
                                                                        // Historically, the BOLTs were unclear if the message type
                                                                        // bytes should be included here or not. The BOLTs have now
                                                                        // been updated to indicate that they *are* included, but many
                                                                        // nodes still send messages without the type bytes, so we
                                                                        // support both here.
                                                                        // TODO: Switch to hard require the type prefix, as the current
                                                                        // permissiveness introduces the (although small) possibility
                                                                        // that we fail to decode legitimate channel updates that
                                                                        // happen to start with ChannelUpdate::TYPE, i.e., [0x01, 0x02].
                                                                        if update_slice.len() > 2 && update_slice[0..2] == msgs::ChannelUpdate::TYPE.to_be_bytes() {
                                                                                update_slice = &update_slice[2..];
                                                                        } else {
                                                                                log_trace!(logger, "Failure provided features a channel update without type prefix. Deprecated, but allowing for now.");
                                                                        }
                                                                        if let Ok(chan_update) = msgs::ChannelUpdate::read(&mut Cursor::new(&update_slice)) {
                                                                                // if channel_update should NOT have caused the failure:
                                                                                // MAY treat the channel_update as invalid.
                                                                                let is_chan_update_invalid = match error_code & 0xff {
                                                                                        7 => false,
                                                                                        11 => amt_to_forward > chan_update.contents.htlc_minimum_msat,
                                                                                        12 => amt_to_forward
                                                                                                .checked_mul(chan_update.contents.fee_proportional_millionths as u64)
                                                                                                .map(|prop_fee| prop_fee / 1_000_000)
                                                                                                .and_then(|prop_fee| prop_fee.checked_add(chan_update.contents.fee_base_msat as u64))
                                                                                                .map(|fee_msats| route_hop.fee_msat >= fee_msats)
                                                                                                .unwrap_or(false),
                                                                                        13 => route_hop.cltv_expiry_delta as u16 >= chan_update.contents.cltv_expiry_delta,
                                                                                        14 => false, // expiry_too_soon; always valid?
                                                                                        20 => chan_update.contents.flags & 2 == 0,
                                                                                        _ => false, // unknown error code; take channel_update as valid
                                                                                };
                                                                                if is_chan_update_invalid {
                                                                                        // This probably indicates the node which forwarded
                                                                                        // to the node in question corrupted something.
                                                                                        network_update = Some(NetworkUpdate::ChannelFailure {
                                                                                                short_channel_id: route_hop.short_channel_id,
                                                                                                is_permanent: true,
                                                                                        });
                                                                                } else {
                                                                                        // Make sure the ChannelUpdate contains the expected
                                                                                        // short channel id.
                                                                                        if failing_route_hop.short_channel_id == chan_update.contents.short_channel_id {
                                                                                                short_channel_id = Some(failing_route_hop.short_channel_id);
                                                                                        } else {
                                                                                                log_info!(logger, "Node provided a channel_update for which it was not authoritative, ignoring.");
                                                                                        }
                                                                                        network_update = Some(NetworkUpdate::ChannelUpdateMessage {
                                                                                                msg: chan_update,
                                                                                        })
                                                                                };
                                                                        }
                                                                }
                                                        }
                                                        if network_update.is_none() {
                                                                // They provided an UPDATE which was obviously bogus, not worth
                                                                // trying to relay through them anymore.
                                                                network_update = Some(NetworkUpdate::NodeFailure {
                                                                        node_id: route_hop.pubkey,
                                                                        is_permanent: true,
                                                                });
                                                        }
                                                        if short_channel_id.is_none() {
                                                                short_channel_id = Some(route_hop.short_channel_id);
                                                        }
                                                } else if payment_failed {
                                                        // Only blame the hop when a value in the HTLC doesn't match the
                                                        // corresponding value in the onion.
                                                        short_channel_id = match error_code & 0xff {
                                                                18|19 => Some(route_hop.short_channel_id),
                                                                _ => None,
                                                        };
                                                } else {
                                                        // We can't understand their error messages and they failed to
                                                        // forward...they probably can't understand our forwards so its
                                                        // really not worth trying any further.
                                                        network_update = Some(NetworkUpdate::NodeFailure {
                                                                node_id: route_hop.pubkey,
                                                                is_permanent: true,
                                                        });
                                                        short_channel_id = Some(route_hop.short_channel_id);
                                                }

                                                res = Some((network_update, short_channel_id, !(error_code & PERM == PERM && is_from_final_node)));

                                                let (description, title) = errors::get_onion_error_description(error_code);
                                                if debug_field_size > 0 && err_packet.failuremsg.len() >= 4 + debug_field_size {
                                                        log_info!(logger, "Onion Error[from {}: {}({:#x}) {}({})] {}", route_hop.pubkey, title, error_code, debug_field, log_bytes!(&err_packet.failuremsg[4..4+debug_field_size]), description);
                                                }
                                                else {
                                                        log_info!(logger, "Onion Error[from {}: {}({:#x})] {}", route_hop.pubkey, title, error_code, description);
                                                }
                                        } else {
                                                // Useless packet that we can't use but it passed HMAC, so it
                                                // definitely came from the peer in question
                                                let network_update = Some(NetworkUpdate::NodeFailure {
                                                        node_id: route_hop.pubkey,
                                                        is_permanent: true,
                                                });
                                                let short_channel_id = Some(route_hop.short_channel_id);
                                                res = Some((network_update, short_channel_id, !is_from_final_node));
                                        }
                                }
                        }
                }).expect("Route that we sent via spontaneously grew invalid keys in the middle of it?");
                if let Some((channel_update, short_channel_id, payment_retryable)) = res {
                        (channel_update, short_channel_id, payment_retryable, error_code_ret, error_packet_ret)
                } else {
                        // only not set either packet unparseable or hmac does not match with any
                        // payment not retryable only when garbage is from the final node
                        (None, None, !is_from_final_node, None, None)
                }
        } else { unreachable!(); }
}

/// An input used when decoding an onion packet.
pub(crate) trait DecodeInput {
        type Arg;
        /// If Some, this is the input when checking the hmac of the onion packet.
        fn payment_hash(&self) -> Option<&PaymentHash>;
        /// Read argument when decrypting our hop payload.
        fn read_arg(self) -> Self::Arg;
}

impl DecodeInput for PaymentHash {
        type Arg = ();
        fn payment_hash(&self) -> Option<&PaymentHash> {
                Some(self)
        }
        fn read_arg(self) -> Self::Arg { () }
}

impl DecodeInput for SharedSecret {
        type Arg = SharedSecret;
        fn payment_hash(&self) -> Option<&PaymentHash> {
                None
        }
        fn read_arg(self) -> Self::Arg { self }
}

/// Allows `decode_next_hop` to return the next hop packet bytes for either payments or onion
/// message forwards.
pub(crate) trait NextPacketBytes: AsMut<[u8]> {
        fn new(len: usize) -> Self;
}

impl NextPacketBytes for FixedSizeOnionPacket {
        fn new(_len: usize) -> Self  {
                Self([0 as u8; ONION_DATA_LEN])
        }
}

impl NextPacketBytes for Vec<u8> {
        fn new(len: usize) -> Self {
                vec![0 as u8; len]
        }
}

/// Data decrypted from a payment's onion payload.
pub(crate) enum Hop {
        /// This onion payload was for us, not for forwarding to a next-hop. Contains information for
        /// verifying the incoming payment.
        Receive(msgs::OnionHopData),
        /// This onion payload needs to be forwarded to a next-hop.
        Forward {
                /// Onion payload data used in forwarding the payment.
                next_hop_data: msgs::OnionHopData,
                /// HMAC of the next hop's onion packet.
                next_hop_hmac: [u8; 32],
                /// Bytes of the onion packet we're forwarding.
                new_packet_bytes: [u8; ONION_DATA_LEN],
        },
}

/// Error returned when we fail to decode the onion packet.
#[derive(Debug)]
pub(crate) enum OnionDecodeErr {
        /// The HMAC of the onion packet did not match the hop data.
        Malformed {
                err_msg: &'static str,
                err_code: u16,
        },
        /// We failed to decode the onion payload.
        Relay {
                err_msg: &'static str,
                err_code: u16,
        },
}

pub(crate) fn decode_next_payment_hop(shared_secret: [u8; 32], hop_data: &[u8], hmac_bytes: [u8; 32], payment_hash: PaymentHash) -> Result<Hop, OnionDecodeErr> {
        match decode_next_hop(shared_secret, hop_data, hmac_bytes, payment_hash) {
                Ok((next_hop_data, None)) => Ok(Hop::Receive(next_hop_data)),
                Ok((next_hop_data, Some((next_hop_hmac, FixedSizeOnionPacket(new_packet_bytes))))) => {
                        Ok(Hop::Forward {
                                next_hop_data,
                                next_hop_hmac,
                                new_packet_bytes
                        })
                },
                Err(e) => Err(e),
        }
}

pub(crate) fn decode_next_hop<D: DecodeInput, R: ReadableArgs<D::Arg>, N: NextPacketBytes>(shared_secret: [u8; 32], hop_data: &[u8], hmac_bytes: [u8; 32], decode_input: D) -> Result<(R, Option<([u8; 32], N)>), OnionDecodeErr> {
        let (rho, mu) = gen_rho_mu_from_shared_secret(&shared_secret);
        let mut hmac = HmacEngine::<Sha256>::new(&mu);
        hmac.input(hop_data);
        if let Some(payment_hash) = decode_input.payment_hash() {
                hmac.input(&payment_hash.0[..]);
        }
        if !fixed_time_eq(&Hmac::from_engine(hmac).into_inner(), &hmac_bytes) {
                return Err(OnionDecodeErr::Malformed {
                        err_msg: "HMAC Check failed",
                        err_code: 0x8000 | 0x4000 | 5,
                });
        }

        let mut chacha = ChaCha20::new(&rho, &[0u8; 8]);
        let mut chacha_stream = ChaChaReader { chacha: &mut chacha, read: Cursor::new(&hop_data[..]) };
        match R::read(&mut chacha_stream, decode_input.read_arg()) {
                Err(err) => {
                        let error_code = match err {
                                msgs::DecodeError::UnknownVersion => 0x4000 | 1, // unknown realm byte
                                msgs::DecodeError::UnknownRequiredFeature|
                                msgs::DecodeError::InvalidValue|
                                msgs::DecodeError::ShortRead => 0x4000 | 22, // invalid_onion_payload
                                _ => 0x2000 | 2, // Should never happen
                        };
                        return Err(OnionDecodeErr::Relay {
                                err_msg: "Unable to decode our hop data",
                                err_code: error_code,
                        });
                },
                Ok(msg) => {
                        let mut hmac = [0; 32];
                        if let Err(_) = chacha_stream.read_exact(&mut hmac[..]) {
                                return Err(OnionDecodeErr::Relay {
                                        err_msg: "Unable to decode our hop data",
                                        err_code: 0x4000 | 22,
                                });
                        }
                        if hmac == [0; 32] {
                                #[cfg(test)]
                                {
                                        // In tests, make sure that the initial onion packet data is, at least, non-0.
                                        // We could do some fancy randomness test here, but, ehh, whatever.
                                        // This checks for the issue where you can calculate the path length given the
                                        // onion data as all the path entries that the originator sent will be here
                                        // as-is (and were originally 0s).
                                        // Of course reverse path calculation is still pretty easy given naive routing
                                        // algorithms, but this fixes the most-obvious case.
                                        let mut next_bytes = [0; 32];
                                        chacha_stream.read_exact(&mut next_bytes).unwrap();
                                        assert_ne!(next_bytes[..], [0; 32][..]);
                                        chacha_stream.read_exact(&mut next_bytes).unwrap();
                                        assert_ne!(next_bytes[..], [0; 32][..]);
                                }
                                return Ok((msg, None)); // We are the final destination for this packet
                        } else {
                                let mut new_packet_bytes = N::new(hop_data.len());
                                let read_pos = hop_data.len() - chacha_stream.read.position() as usize;
                                chacha_stream.read_exact(&mut new_packet_bytes.as_mut()[..read_pos]).unwrap();
                                #[cfg(debug_assertions)]
                                {
                                        // Check two things:
                                        // a) that the behavior of our stream here will return Ok(0) even if the TLV
                                        //    read above emptied out our buffer and the unwrap() wont needlessly panic
                                        // b) that we didn't somehow magically end up with extra data.
                                        let mut t = [0; 1];
                                        debug_assert!(chacha_stream.read(&mut t).unwrap() == 0);
                                }
                                // Once we've emptied the set of bytes our peer gave us, encrypt 0 bytes until we
                                // fill the onion hop data we'll forward to our next-hop peer.
                                chacha_stream.chacha.process_in_place(&mut new_packet_bytes.as_mut()[read_pos..]);
                                return Ok((msg, Some((hmac, new_packet_bytes)))) // This packet needs forwarding
                        }
                },
        }
}

#[cfg(test)]
mod tests {
        use io;
        use prelude::*;
        use ln::PaymentHash;
        use ln::features::{ChannelFeatures, NodeFeatures};
        use routing::router::{Route, RouteHop};
        use ln::msgs;
        use util::ser::{Writeable, Writer};

        use hex;

        use bitcoin::secp256k1::Secp256k1;
        use bitcoin::secp256k1::{PublicKey,SecretKey};

        use super::OnionKeys;

        fn build_test_onion_keys() -> Vec<OnionKeys> {
                // Keys from BOLT 4, used in both test vector tests
                let secp_ctx = Secp256k1::new();

                let route = Route {
                        paths: vec![vec![
                                        RouteHop {
                                                pubkey: PublicKey::from_slice(&hex::decode("02eec7245d6b7d2ccb30380bfbe2a3648cd7a942653f5aa340edcea1f283686619").unwrap()[..]).unwrap(),
                                                channel_features: ChannelFeatures::empty(), node_features: NodeFeatures::empty(),
                                                short_channel_id: 0, fee_msat: 0, cltv_expiry_delta: 0 // Test vectors are garbage and not generateble from a RouteHop, we fill in payloads manually
                                        },
                                        RouteHop {
                                                pubkey: PublicKey::from_slice(&hex::decode("0324653eac434488002cc06bbfb7f10fe18991e35f9fe4302dbea6d2353dc0ab1c").unwrap()[..]).unwrap(),
                                                channel_features: ChannelFeatures::empty(), node_features: NodeFeatures::empty(),
                                                short_channel_id: 0, fee_msat: 0, cltv_expiry_delta: 0 // Test vectors are garbage and not generateble from a RouteHop, we fill in payloads manually
                                        },
                                        RouteHop {
                                                pubkey: PublicKey::from_slice(&hex::decode("027f31ebc5462c1fdce1b737ecff52d37d75dea43ce11c74d25aa297165faa2007").unwrap()[..]).unwrap(),
                                                channel_features: ChannelFeatures::empty(), node_features: NodeFeatures::empty(),
                                                short_channel_id: 0, fee_msat: 0, cltv_expiry_delta: 0 // Test vectors are garbage and not generateble from a RouteHop, we fill in payloads manually
                                        },
                                        RouteHop {
                                                pubkey: PublicKey::from_slice(&hex::decode("032c0b7cf95324a07d05398b240174dc0c2be444d96b159aa6c7f7b1e668680991").unwrap()[..]).unwrap(),
                                                channel_features: ChannelFeatures::empty(), node_features: NodeFeatures::empty(),
                                                short_channel_id: 0, fee_msat: 0, cltv_expiry_delta: 0 // Test vectors are garbage and not generateble from a RouteHop, we fill in payloads manually
                                        },
                                        RouteHop {
                                                pubkey: PublicKey::from_slice(&hex::decode("02edabbd16b41c8371b92ef2f04c1185b4f03b6dcd52ba9b78d9d7c89c8f221145").unwrap()[..]).unwrap(),
                                                channel_features: ChannelFeatures::empty(), node_features: NodeFeatures::empty(),
                                                short_channel_id: 0, fee_msat: 0, cltv_expiry_delta: 0 // Test vectors are garbage and not generateble from a RouteHop, we fill in payloads manually
                                        },
                        ]],
                        payment_params: None,
                };

                let session_priv = SecretKey::from_slice(&hex::decode("4141414141414141414141414141414141414141414141414141414141414141").unwrap()[..]).unwrap();

                let onion_keys = super::construct_onion_keys(&secp_ctx, &route.paths[0], &session_priv).unwrap();
                assert_eq!(onion_keys.len(), route.paths[0].len());
                onion_keys
        }

        #[test]
        fn onion_vectors() {
                // Legacy packet creation test vectors from BOLT 4
                let onion_keys = build_test_onion_keys();

                assert_eq!(onion_keys[0].shared_secret.secret_bytes(), hex::decode("53eb63ea8a3fec3b3cd433b85cd62a4b145e1dda09391b348c4e1cd36a03ea66").unwrap()[..]);
                assert_eq!(onion_keys[0].blinding_factor[..], hex::decode("2ec2e5da605776054187180343287683aa6a51b4b1c04d6dd49c45d8cffb3c36").unwrap()[..]);
                assert_eq!(onion_keys[0].ephemeral_pubkey.serialize()[..], hex::decode("02eec7245d6b7d2ccb30380bfbe2a3648cd7a942653f5aa340edcea1f283686619").unwrap()[..]);
                assert_eq!(onion_keys[0].rho, hex::decode("ce496ec94def95aadd4bec15cdb41a740c9f2b62347c4917325fcc6fb0453986").unwrap()[..]);
                assert_eq!(onion_keys[0].mu, hex::decode("b57061dc6d0a2b9f261ac410c8b26d64ac5506cbba30267a649c28c179400eba").unwrap()[..]);

                assert_eq!(onion_keys[1].shared_secret.secret_bytes(), hex::decode("a6519e98832a0b179f62123b3567c106db99ee37bef036e783263602f3488fae").unwrap()[..]);
                assert_eq!(onion_keys[1].blinding_factor[..], hex::decode("bf66c28bc22e598cfd574a1931a2bafbca09163df2261e6d0056b2610dab938f").unwrap()[..]);
                assert_eq!(onion_keys[1].ephemeral_pubkey.serialize()[..], hex::decode("028f9438bfbf7feac2e108d677e3a82da596be706cc1cf342b75c7b7e22bf4e6e2").unwrap()[..]);
                assert_eq!(onion_keys[1].rho, hex::decode("450ffcabc6449094918ebe13d4f03e433d20a3d28a768203337bc40b6e4b2c59").unwrap()[..]);
                assert_eq!(onion_keys[1].mu, hex::decode("05ed2b4a3fb023c2ff5dd6ed4b9b6ea7383f5cfe9d59c11d121ec2c81ca2eea9").unwrap()[..]);

                assert_eq!(onion_keys[2].shared_secret.secret_bytes(), hex::decode("3a6b412548762f0dbccce5c7ae7bb8147d1caf9b5471c34120b30bc9c04891cc").unwrap()[..]);
                assert_eq!(onion_keys[2].blinding_factor[..], hex::decode("a1f2dadd184eb1627049673f18c6325814384facdee5bfd935d9cb031a1698a5").unwrap()[..]);
                assert_eq!(onion_keys[2].ephemeral_pubkey.serialize()[..], hex::decode("03bfd8225241ea71cd0843db7709f4c222f62ff2d4516fd38b39914ab6b83e0da0").unwrap()[..]);
                assert_eq!(onion_keys[2].rho, hex::decode("11bf5c4f960239cb37833936aa3d02cea82c0f39fd35f566109c41f9eac8deea").unwrap()[..]);
                assert_eq!(onion_keys[2].mu, hex::decode("caafe2820fa00eb2eeb78695ae452eba38f5a53ed6d53518c5c6edf76f3f5b78").unwrap()[..]);

                assert_eq!(onion_keys[3].shared_secret.secret_bytes(), hex::decode("21e13c2d7cfe7e18836df50872466117a295783ab8aab0e7ecc8c725503ad02d").unwrap()[..]);
                assert_eq!(onion_keys[3].blinding_factor[..], hex::decode("7cfe0b699f35525029ae0fa437c69d0f20f7ed4e3916133f9cacbb13c82ff262").unwrap()[..]);
                assert_eq!(onion_keys[3].ephemeral_pubkey.serialize()[..], hex::decode("031dde6926381289671300239ea8e57ffaf9bebd05b9a5b95beaf07af05cd43595").unwrap()[..]);
                assert_eq!(onion_keys[3].rho, hex::decode("cbe784ab745c13ff5cffc2fbe3e84424aa0fd669b8ead4ee562901a4a4e89e9e").unwrap()[..]);
                assert_eq!(onion_keys[3].mu, hex::decode("5052aa1b3d9f0655a0932e50d42f0c9ba0705142c25d225515c45f47c0036ee9").unwrap()[..]);

                assert_eq!(onion_keys[4].shared_secret.secret_bytes(), hex::decode("b5756b9b542727dbafc6765a49488b023a725d631af688fc031217e90770c328").unwrap()[..]);
                assert_eq!(onion_keys[4].blinding_factor[..], hex::decode("c96e00dddaf57e7edcd4fb5954be5b65b09f17cb6d20651b4e90315be5779205").unwrap()[..]);
                assert_eq!(onion_keys[4].ephemeral_pubkey.serialize()[..], hex::decode("03a214ebd875aab6ddfd77f22c5e7311d7f77f17a169e599f157bbcdae8bf071f4").unwrap()[..]);
                assert_eq!(onion_keys[4].rho, hex::decode("034e18b8cc718e8af6339106e706c52d8df89e2b1f7e9142d996acf88df8799b").unwrap()[..]);
                assert_eq!(onion_keys[4].mu, hex::decode("8e45e5c61c2b24cb6382444db6698727afb063adecd72aada233d4bf273d975a").unwrap()[..]);

                // Test vectors below are flat-out wrong: they claim to set outgoing_cltv_value to non-0 :/
                let payloads = vec!(
                        msgs::OnionHopData {
                                format: msgs::OnionHopDataFormat::Legacy {
                                        short_channel_id: 0,
                                },
                                amt_to_forward: 0,
                                outgoing_cltv_value: 0,
                        },
                        msgs::OnionHopData {
                                format: msgs::OnionHopDataFormat::Legacy {
                                        short_channel_id: 0x0101010101010101,
                                },
                                amt_to_forward: 0x0100000001,
                                outgoing_cltv_value: 0,
                        },
                        msgs::OnionHopData {
                                format: msgs::OnionHopDataFormat::Legacy {
                                        short_channel_id: 0x0202020202020202,
                                },
                                amt_to_forward: 0x0200000002,
                                outgoing_cltv_value: 0,
                        },
                        msgs::OnionHopData {
                                format: msgs::OnionHopDataFormat::Legacy {
                                        short_channel_id: 0x0303030303030303,
                                },
                                amt_to_forward: 0x0300000003,
                                outgoing_cltv_value: 0,
                        },
                        msgs::OnionHopData {
                                format: msgs::OnionHopDataFormat::Legacy {
                                        short_channel_id: 0x0404040404040404,
                                },
                                amt_to_forward: 0x0400000004,
                                outgoing_cltv_value: 0,
                        },
                );

                let packet: msgs::OnionPacket = super::construct_onion_packet_with_init_noise::<_, _>(payloads, onion_keys, super::FixedSizeOnionPacket([0; super::ONION_DATA_LEN]), Some(&PaymentHash([0x42; 32])));
                // Just check the final packet encoding, as it includes all the per-hop vectors in it
                // anyway...
                assert_eq!(packet.encode(), hex::decode("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").unwrap());
        }

        #[test]
        fn test_failure_packet_onion() {
                // Returning Errors test vectors from BOLT 4

                let onion_keys = build_test_onion_keys();
                let onion_error = super::build_failure_packet(onion_keys[4].shared_secret.as_ref(), 0x2002, &[0; 0]);
                assert_eq!(onion_error.encode(), hex::decode("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").unwrap());

                let onion_packet_1 = super::encrypt_failure_packet(onion_keys[4].shared_secret.as_ref(), &onion_error.encode()[..]);
                assert_eq!(onion_packet_1.data, hex::decode("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").unwrap());

                let onion_packet_2 = super::encrypt_failure_packet(onion_keys[3].shared_secret.as_ref(), &onion_packet_1.data[..]);
                assert_eq!(onion_packet_2.data, hex::decode("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").unwrap());

                let onion_packet_3 = super::encrypt_failure_packet(onion_keys[2].shared_secret.as_ref(), &onion_packet_2.data[..]);
                assert_eq!(onion_packet_3.data, hex::decode("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").unwrap());

                let onion_packet_4 = super::encrypt_failure_packet(onion_keys[1].shared_secret.as_ref(), &onion_packet_3.data[..]);
                assert_eq!(onion_packet_4.data, hex::decode("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").unwrap());

                let onion_packet_5 = super::encrypt_failure_packet(onion_keys[0].shared_secret.as_ref(), &onion_packet_4.data[..]);
                assert_eq!(onion_packet_5.data, hex::decode("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").unwrap());
        }

        struct RawOnionHopData {
                data: Vec<u8>
        }
        impl RawOnionHopData {
                fn new(orig: msgs::OnionHopData) -> Self {
                        Self { data: orig.encode() }
                }
        }
        impl Writeable for RawOnionHopData {
                fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
                        writer.write_all(&self.data[..])
                }
        }

        #[test]
        fn variable_length_onion_vectors() {
                // Packet creation test vectors from BOLT 4 (as of this writing at
                // bolt04/onion-test-multi-frame.json in the spec repo).
                // Note that we use he RawOnionHopData for everything except Legacy hops, as even the hops
                // with "type": "tlv" are not valid TLV (they were for a previous version of TLV that
                // didn't move forward), and, thus, cannot be directly represented in our in-memory enums.
                let onion_keys = build_test_onion_keys();

                let payloads = vec!(
                        RawOnionHopData::new(msgs::OnionHopData {
                                format: msgs::OnionHopDataFormat::Legacy {
                                        short_channel_id: 0,
                                },
                                amt_to_forward: 0,
                                outgoing_cltv_value: 0,
                        }),
                        RawOnionHopData {
                                data: hex::decode("140101010101010101000000000000000100000001").unwrap(),
                        },
                        RawOnionHopData {
                                data: hex::decode("fd0100000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f202122232425262728292a2b2c2d2e2f303132333435363738393a3b3c3d3e3f404142434445464748494a4b4c4d4e4f505152535455565758595a5b5c5d5e5f606162636465666768696a6b6c6d6e6f707172737475767778797a7b7c7d7e7f808182838485868788898a8b8c8d8e8f909192939495969798999a9b9c9d9e9fa0a1a2a3a4a5a6a7a8a9aaabacadaeafb0b1b2b3b4b5b6b7b8b9babbbcbdbebfc0c1c2c3c4c5c6c7c8c9cacbcccdcecfd0d1d2d3d4d5d6d7d8d9dadbdcdddedfe0e1e2e3e4e5e6e7e8e9eaebecedeeeff0f1f2f3f4f5f6f7f8f9fafbfcfdfeff").unwrap(),
                        },
                        RawOnionHopData {
                                data: hex::decode("140303030303030303000000000000000300000003").unwrap(),
                        },
                        RawOnionHopData::new(msgs::OnionHopData {
                                format: msgs::OnionHopDataFormat::Legacy {
                                        short_channel_id: 0x0404040404040404,
                                },
                                amt_to_forward: 4,
                                outgoing_cltv_value: 4,
                        }),
                );

                let packet: msgs::OnionPacket = super::construct_onion_packet_with_init_noise::<_, _>(payloads, onion_keys, super::FixedSizeOnionPacket([0; super::ONION_DATA_LEN]), Some(&PaymentHash([0x42; 32])));
                // Just check the final packet encoding, as it includes all the per-hop vectors in it
                // anyway...
                assert_eq!(packet.encode(), hex::decode("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").unwrap());
        }
}